Since all the observations were done towards the direction of brightest emission from CH3OH lines at 290\(\,{}\)  near the OH maser regions, our data lacks the scope to allow us to determine the extent of the molecular emission. Looking at the extended nature of CO emissions mapped by [1]} (see their Fig. 1a) and [2]} (see their Fig. 1), we may assume that the emission from other molecules is also extended in nature, which would correspond to a beam-filling factor of 1. However, this assumption may not be entirely true, in which case, a beam dilution factor needs to be assumed. Apart from the standard calibration error associated with APEX data, this unknown beam-filling factor is the largest source of uncertainty when scaling line intensities to account for differences in beamsize caused by different observing frequencies. In order to quantify how this impacts the results, all the analyses presented throughout this paper were carried out for two extreme cases: a point like source and an extended source covering the whole beam. The results obtained for a point-like source were not significantly different from those of the extended source when a 20% uncertainty was assumed while scaling the line intensities for the latter. Therefore, all results presented in this paper correspond to the case of an extended source with a beam-filling factor of 1 along with a 20% uncertainty added while scaling intensities to account for differences in beam size.
